Before World War II, we used to follow the Geneva Convention Rules of War when possible or expedient. We tried not to harm civilians. Sometime during World War II that changed, and we began to deliberately target civilians in both Germany and Japan. Dresden and Tokyo were firebombed with the newly-developed napalm. The canisters had been designed to break through the roof of an average home and detonate in the living room. The fire storms caused by napalm killed hundreds of thousands, many more people than died from atomic weapons. Regarding the Rules of War, seems like the gloves came off and they never went back on.
We chose Hiroshima and Nagasaki for the new A bombs because they were the only cities of size that had not already been repeatedly firebombed. In his radio announcement of the dropping of “Big Boy” on Hiroshima, Truman calls it a “military target.” Sure Harry, whatever gets you through the night.
Amazingly, after the Trumans left the White House they drove cross-country unaccompanied by any Secret Service protection. They drove from Kansas City to New York City, took in a show, stayed in hotels, ate in restaurants, and then drove home. You would have thought maybe they might have bumped into a person of Japanese, Korean or German ancestry who might have held a grudge, but apparently they didn’t and the prospect never crossed Harry’s mind.
In Korea we used napalm extensively on the inhabitants of what is now North Korea. The Koreans and the Chinese fatalities amounted to about three million people versus 33,000 American dead. Then in Vietnam and Laos, we repeated our fascination with dousing non-compliant civilians with burning rain. Again, they lost many more people than we did.
You don’t hear much about napalm anymore. Now we have drone-launched missiles that can be target to fly through an open window.